Mechanism for finishing cylindrical surfaces



April 1, 1952 L. LOWY ETIAL 2,591,273 MECHANISM FOR FINISHING CYLINDRICAL SURFACES Filed March 5, 194a INVENTORS Lou/s Lou/g Ci Siam/6g 73.57712 BY WK ATTOP/VEK Patented Apr. 1, 1952 MECHANISM FOR FINISHING CYLIN- DRICAL SURFACES Louis Lowy and Stanley R. Emig, Detroit, Mich.

Application March 5, 1949, Serial No. 79,802

1 Claim.

This invention relates to cutting tools, and more particularly to cutting tools formed of the so-called hard metals adapted to simultaneously rotate and reciprocate within a cylindrical surface to produce an axially straight, true cylindrical, smooth surface.

In many industrial operations it is necessary that true cylindrical surfaces be axially straight. A honing process has heretofore been extensively used in the formation of such surfaces with a considerable degree of success. The .abradins' stones used in the honing process are expensive, and quickly wear to such an extent that a desired degree of accuracy cannot be achieved. In an effort to overcome these difiiculties it has been common practice to perform roughing and finishing operations. This expedient increases the necessary handling of parts being processed, and necessitates the duplication of equipmentif a production schedule must be maintained, as in the automotive industry where the boring of engine cylinders is an important operation.

An object of this invention is to provide an improved method of forming axially straight true cylindrical surfaces.

A further object of the invention resides in the development of an improved method of finlshing cylindrical surfaces in such a manner that a single operation is sufficient to produce the desired accurately contoured smooth surfaces, thereby minimizing the required equipment and accelerating the maintenance of production schedules.

Another object of this invention resides in the use of expanding cutters formed of the so-called hard metals such as the carbides, Stellites and tungsten alloys to form accurate cylindrical surfaces.

Yet a still further object of the invention is to facilitate the finishing of accurately contoured cylindrical surfaces by using expansible hard alloy cutters adapted to be rotated and reciprocated within a cylindrical bore to form an accurate smooth surface therein.

Another object of the invention resides in the development of a hard alloy cutter that can be substituted for the abrading stones of a honing machine to provide true cylindrical axially straight bores.

..Further objects and advantages of the invention will be apparent-from the following description, taken in connection with the appended drawings, in which:

Fig. 1 is a sectional view of a cutter embodying our invention.

Fig. 2 is a perspective view of one of the cutter members illustrated in Fig. 1.

Fig. 3 is a view similar to Fig. 2 illustrating a modified form of cutter member.

Fig. 4 is also a view similar to Fig. 2 illustrating a still further modified form of cutter member.

It is understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for purpose of description and not of limitation.

Referring now more particularly to Fig. 1 it will be noted that a body member ID is provided with a centrally disposed axially extending cylinder I2 adapted to receive spaced actuating members l4 and [6 having axially straight segments l8 and 20 respectively to guide them in the cylinder. The actuating members also have conical actuating portions 2| and 24 to bear against the angularly related surfaces 26 and 28 of plungers 30 and 32 secured to spaced relatively movable cutter carrying members 34 and 36. A spring 38 interposed between the axially straight segments l8 and 20 of the actuating members I4 and I6 is provided to exert a radially outwardly directed force on the plungers 30 and 32 thereby urging the cutter carrying members 34 and 38 outwardly. I

As more clearly illustrated in Fig. 2 the cutter carrying members 34 and 36 are preferably channel shaped having a base 40 and spaced upstand ing flanges 42. A plurality of cutter elements preferably formed 'ofspaced laminations N formed of the so-called hard alloys such for example as the hard carbides, tungsten, Stellite, tantalum, titanium, etc. are positioned in the carriers 34 and 36 and are preferably spaced apart by means of spacers 46 in such a manner that their cutting edges 48 are free to operate individually. It will of course be apparent thatif desired solid blocks of hard alloy materials having grooves cut therein to provide clearance angles for the cutting edges maybe employed.

We prefer that the spaced laminations 44 forming the cutters be so proportioned that the cutting edge 48 of the leading lamination 44 have its cutting edge 48 positioned slightly closer to the axial center of the body member l0, and that the successive following cutters have their cutting edges 48 positioned progressively slightly farther from the axial center of the member ID to provide successively operating cutting edges. The radial portions of the cutters positloned behind the cutting edges 48 of the respective cutters 44 are of course relieved to provide suitable clearance angles.

The laminations 44 are assembled with the spacers 46 to position the cutting edges 48 of the cutters as indicated above and the assembly thus formed is secured together in any convenient manner as by copper brazing or other fusion or mechanical means that will not injure the alloys of which the cutters are formed. The assemblies thus formed may be secured in the cutter carrying members 34 and 36 in any convenient mechanical or fusing manner.

The cutters thus formed may be assembled in the body member and retained in place therein by any suitable means such as by springs 50. Any desired number of cutter assemblies may of course be mounted on the body member 10.

While we have shown-a spring 38 for urging the cutter assemblies radially outwardly, .into contact with the cylindrical surface to be treated, it will beapparent, that any other convenient means may be employed, such for example as hydraulically or otherwise actuated means.

The body member is provided with a shank 52 secured through auniversal joint 54 to a driving shaft l'zfi preferably secured throughanother universal joint to a driving member adapted to be rotated and reciprocated in the cylinder to be treated.

- The cutter elements 44 are thus urged radially outwardly to position their cutting edges 48 in .contactwith the inner surface of the cylinder to be-treated. The cutters are rotated within the cylinder and are reciprocated back and forth in the cylinder .The cutting edges 48 shear metal engines If desired automatically operable means associated with the cutter supporting mechanism. may be provided to stop the machine when the cylinder being treated has at tained the desired diameter.

Attention is directed to the fact .that the :cutters44 being formed of the hard alloys are very long .lived and retain their cutting edges 48 in sharp .condition for an extended period oftime. When the cutting edges 48 have dulled tosuch bers 44 may be sharpened in the carrying members 34 and 36 or they may be removed therefrom and separated so thatv they can be resharpened individually. If the cutter elements 44 are secured together as by a grazing operation they may be heated to the brazing temperature to separate them, and rebraz ed together after they have been sharpened.

Fig. 3 illustrates a modified form of the invention wherein cutter elements having curved cutting edges 62 are employed. It will be noted that as this type of cutter is rotated in the direction of the arrow 64 and reciprocated in a cylinder the angularly related cutting edges are disposed in such a manner as to perform a more efficient finishing operation on the internal surface of the cylinder being treated.

axially of the carrying member 34 to be operative as the cutters 66 are rotated in the direction of the arrow 80, and transversely extending cutter surfaces 82 and 04 adapted to be operative by the reciprocating movement of the cutter assembly in the cylinder being treated.

In view of the long life of the hard cutter elements employed resharpening is very infrequent and we are able to form true cylindrical, axially straight surfaces by a single operation. Indexing of work to other machines, and the investment required to provide substantially duplicate machines to perform roughing and finishing operations are thus saved. These savings coupled with the considerable savings effected by eliminating the necessity of frequent replacement of stones used in the honing operation make our invention commercially desirable, and in addition we are able to provide more accurate surfaces.

It will be understood that various othertypes of cutting elements may be substituted for those illustrated, the essence of our invention residing in the use of cutter elements formed of inherently hard alloys shaped and contoured in such a manner as to insure rapid and accurate finishing of cylindrical surfaces to provide cylindrically true axially straight smooth surfaces.

We claim: v A cutting tool for forming a true cylindrica axially straight smooth surface in a cylinder comprising a body member adapted. to be simultaneously rotated and reciprocated and having an axially extending cylinder, a plurality of spaced cutter carrying members including radially extending plungers projecting through radially extending apertures in the body member and having angularly related actuating surfaces, spaced actuating members slidably mounted in the cylinder of the body member and having conical actuating. portions engaging the angularly related surfaces of said plungers, yielding means between said spaced actuating members urging the cutter carrying members radially outwardly, a plurality of hard alloy cutting elements secured to the cutter carrying members for rotation and reciprocation therewith and each having a plurality of spaced wear resistant laminations each having an axially straight cutting edge, and spacers interposed between successive laminations, the cutting edge of eachsuccessive lamination in the direction of rotation being positioned radially inwardly from the cutting edge of the preceding lamination to induce the cutting edges of all of said laminations to be simultaneously operative.

LOUIS LOWY. I STANLEY R. EMIG. REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

